I noticed the same thing when moving from the 0.98 to 1.0+ version of Sencha. The text also is not as "crisp" (appears a bit blurry to my eye) in the 1.0+ style sheets. If you were to revert back to a pre-1.0 stylesheet, the headers would appear as shown in the docs screenshot. I'm hoping they revert back to the prior heading style in a future release as it was much more pleasing IMHO.